Controlling device for electric heaters



A. LONGORIA.

CONTROLLING DEVICE FOR ELECTRIC HEATERS.

APPLICATION FILED 1UNE30, 1920.

1,41 6,482. Patented May lfi, 192-7 UNITED STATES ANTONIO LONGORIA, OF CLEVELAND, OHIO.

CONTROLLING DEVICE FOR ELECTRIC HEATERS.

Specification of Letters Patent. Patented May 16, 1922.

Application filed June 30, 1920. Serial No. 393,062.

To all whom it may concern:

Be it known that I, ANTONIO LONGORIA, a

citizen of the United States, residing at.

Cleveland, in the county of Ouyahoga and State of Ohio, have invented certain new and useful Improvements in Controlling De.- vices for Electric Heaters, of which the following is a specification.

This invention relates to electric heating devices and more particularly to thermostatic control devices therefor.

The objects of the invention are to provide an improved heating device capable of carrying high current and producing maximum heating results, but which nevertheless is also thermostatically controlled by a switch whichis automatically opened and closed without appreciable or dangerous arcing; to provide a device of this kind which can be readily applied for use in heating many different materials or devices; and to provide an improved thermostatically operated controller for heating devices of this kind which is of simple form,

which is accurate and reliable in operation, which can be readily adjusted to vary the working temperature, and which is not liable to get out of order in service.

Further objects of the invention are 1n part obvious and in part will appear more in detail hereinafter.

The invention comprises the construction and arrangement of parts hereinafter described and claimed. 1

In the drawings, Fig. 1 is a diagrammatlc view illustrating one form of the invention; Figs. 2, 2, 3, and 4 are similar views illustra'ting still other forms of the invention; Fig. 5 is a sectional elevation of the thermo- 4 static device, showing the same applied to a water container; Fig. 6 is a plan view of the removable member of the thermostatic device, partly broken away and in section to expose lnterior parts; and Fig. 7, is a detail view of a modification.

The invention is applicable for use in connection with either D. C. or A. O. current and is particularly adapted for use in control ling circuits of high amperage, such circuits as heretofore have not been successfully thermostatically controlled because of the heavy arcing at the gap or switch. The invention comprises a suitable heating unit through which current is passed to generate heat, a thermally controlled switch for controlling the fiow of current to said unit, and

a suitable condenser having the requisite capacity and properly designed and constructed to absorb the heavy rush of current and avoid undue or deleterious arcing at the switch contact points.

Fig. 1 illustrates diagrammatically a simple form of the invention including a. heating unit H connected by the wires 1 to the lead wires 2. One of the wires 1 includes an automatically controlled switch 3, later to be described in detail, for controlling the flow of current through the heating unit. This switch is located in heat responsive relation to the unit or to the water'or other liquid, gaseous or solid material to be heated thereby, the arrangement being such that rise in temperature automatically produces a break in the circuit and cuts off the flow of further current, while adrop in temperature closes the circuit.

Ordinarily it has heretofore been impossible, or at least impractical, to use a thermostatically actuated switch for controlling the flow of current to a heating unit. Such devices have only been used in connection with small units or when the current does not exceed a few watts. According to the present invention the heavy rush. of current is absorbed by suitable means, such as a condenser C. In Fig. 1 this condenser is placed in a shunt circuit across the unit, while in Fig. 3 it is located in a shunt circuit around the gap or gaps at the switch 3. Either arrangement will prevent a heavy rush of ourrent acrossthe contact points'and avoids excessive arclng, so that as much as 1400 or more watts can be passed, through the unit. The condenser, of course, must be designed with special reference to the amount of current passing through the points, which is a function of the particular heating unit, said unit being designed according to the quantity of heat desired. The condenser must have the proper capacity with reference to the amount of current used by the heating unit to be able to absorb the are produced. This is merely a matter of calculation.

Fig. 2 shows an arrangement including two units, H and H in parallel through two switches 3, 3*, each of said units having its own condenser C. The arrangement is practically the same asthat in Fig. 1 but in multiple. By increasing the number of units.

any desired heat effect can be secured, the flow of current through each unit being controlled by its own switch.

This arrangement is particularly useful when designing the control devices for a heating unit already constructed. For eigample let us assume that the heating unit H in Fig. 2, is already installed and consumes two kilowatts and must be provided with control devices. In such a case, instead of providing a single switch for controlling the entire heating unit, said unit is divided into two or more sections in parallel, the several sections being controlled by separate switches. Fig. 2 shows a modified form of the arrangement in Fig. 2 in which a single condenser C is in shunt with both sections H, H of the heating unit. This condenser is designed with suflicient capacity to absorb the are when either one of the two switches opens and the switches are set or adjusted so as to open at temperatures differing by a few degrees, say five degrees, so that it is practically impossible for both switches to open or attempt to are at the same time. A single condenser will therefore take care of both of them.

Fig. 4 illustrates another arrangement for exceptionally heavy currents and which embodies a rela In this arrangement the heating unit is in a circuit including a switch S carried by or attached to the core 4 of an electromagnet or solenoid, the coil 5 of which is in a controlling circuit 6 including a thermostatically controlled switch 3 and a condenser G whichmay be across either the coil 5 or the gap. When this circuit 6 is closed the coil 5 is energized and switch S- is moved to close the-gaps 6, '12,, so that current from the line flows directly through the unit H. The switch 3 is in heat responsive relation to the unit H or the material or device heated thereby. The coil 5 may be located anywhere. This arrangement reduces the current to be controlled to that consumed by the coil 5 rather than the heavier current consumed by the unit H.

The invention is 'capable of use in many ways, for example, for heating water or other liquids for heating dental or other vulcanizers, sterilizers, glue pots, coflee urns or other devices or for heating gases or solids. Usually the thermostatically controlled switch is made of special form with reference to the particular use for which the heat is desired or the device to which the heater is to be attached. Figs. 5 and 6 illustrate the invention applied to a container 10 for holding water or other liquid 11 to be heated. Said container is provided with a hollow fitting 12 threaded to receive a hollow cup or casing 13 of brass or other heat conducting material, into which is threaded a removable member 14 carrying the switch parts. This member may be made of conducting material with the current conducting parts insulated therefrom, but as shown it is made of a single piece of insulating material, such as bakelite Or a composition, in which are molded the conducting parts. One of said parts, marked 15, has a threaded opening to receive an adjusting screw 16 terminating in a contact member 17. The other part, marked 18, is riveted 0r otherwise secured to the base of a bent metal loop or arm 19 which is preferably bi-metallic or made of layers of two different metals so as to flex or bend with variations in temperature. That metal having the greater coefficient of expansion is on the inside of the curve. This arm is bent back on itself at 20 and is also bent slightly outwardly, as at 21, the two bends compensating for each other so that the contact 22 carried by the arm moves directly toward and from the contact 17 with no appreciable angular motion. By adjusting the screw 16 the working or operating temperature at which the switch opens or closes ma be readily raised or lowered as desired. oth members 15 and 18 terminate in points or pins 23 adapted toenter sockets or openings in the connector, to which the circuit wires are connected.

This arrangement enables the heater to be readily connected up or disconnected and by taking out the member 14 the switch'may be readily adjusted for any desired temperature.,

Figure 7 illustrates a modified arrangement for connecting members 14 and 13, the latter of which is screwed into the fitting 12, as in the form before described. According to this modification the body portion of member 14 is provided with an annular groove or channel 24 which at one point communicates with a short longitudinal channel 25. The two channels co-operate with a pin 26 in member 13, the whole forming a releasable bayonet joint enabling member 14 to be pushed into place to allow the pin 26 to pass. through channel 25 and into channel 24, after which member 14 can be rotated to any amount without being released. This construction enables member 14 to be turned until the pins 23 are horizontally opposite from each other or in any other desired position where they are most conveniently located for attachment to the connector for connecting the main circuit wires to the switch.

What I claim is:

1. A heating device, including a heatin unit, a thermostatically controlled switcii controlling the flow of current thereto, and means for absorbing the rush. of current when said circuit is opened.

2. A heating device, including a heating unit, a thermostatically controlled switch controlling the flow of current thereto, and acondenser having the proper capacity and arranged to absorb the rush of current when the circuit is broken.

3. A heating device, comprising a heating unit, a hollow casing adapted to be connected in heat responsive relation to the material v heated thereby, a plug member removably connected to said casing, a thermostatically actuated switch carried by said plug member member therein and removable therefrom,'

twocontacts carried thereby, one of said contacts being relatively -fixed, a member carrying the other contact and arranged to bend in response to variations in temperature and carrying the other of said contacts, and means or connecting circuit wires to said contacts. j

5'. Controlling means ior a heating unit, comprising a heat conductive casing, a plug member therein and removable therefrom two contacts carried thereby, one of said contacts being relatively fixed, a member carrying the other contact and arranged to bend in response to variations in temperature and carrying the other of said contacts, means for connecting circuit -wires to said contacts, and means for adjusting said fixed contact to vary the working temperature.

6. A thermostatically controlled switch for electric circuits, comprising a support, a

relatively fixed contact, a loop member formed of layers of two materials with that material having the greater coeflicient of expansion on the inside, and a contact carried thereby.

In testimony whereof I afiix my signature.

' ANTONIO LONGORIA. 

